title: Applying cloud point extraction technique for the extraction of oxazepam from human urine as a colour or fluorescent derivative prior to spectroscopic analysis methods.
abstract: Two new methods based on cloud point extraction (CPE) technique were developed and optimized for the extraction and preconcentration of oxazepam from human urine, as an azo or fluorescent derivative. The first method is a spectrophotometric one, which is based on the acid hydrolysis of the oxazepam to a benzophenone, diazotization of the benzophenone, and then the coupling with oxine to form an azo dye. The second method is a spectrofluorimetric one, which involves reduction of the target compound using Zn°/HCl at room temperature with the formation of a highly fluorescent derivative. The main factors affecting the chemical reactions and CPE were investigated and optimized systematically. Under optimum experimental conditions, the calibration graphs were linear in the range of 0.1 to 1.5 (0.05 to 2.0) µg/ml with correlation coefficients of 0.9989 (0.9985), for the CPE-spectrophotometric (CPE-spectrofluorimetric) method. The limit of detection was found to be 0.034 (0.018) µg/ml and the relative standard deviation was calculated to be 1.35 (2.52)%. Recoveries in the spiked samples ranged from 87 to 94%. Finally, the proposed methods were applied to the determination of oxazepam in human urine.
authors.affiliation: Department of Medicinal Chemistry, Faculty of Pharmacy & Biotechnology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran. a.bavili@tbzmed.ac.ir
authors.forename: Ahad Bavili
authors.initials: AB
authors.lastname: Tabrizi
authors.forename: Maryam
authors.initials: M
authors.lastname: Harasi
mesh_terms: D014151:Anti-Anxiety Agents / Q000302:isolation & purification* / Q000652:urine*; D005591:Chemical Fractionation / Q000379:methods*; D004396:Coloring Agents / Q000737:chemistry*; D006801:Humans; D057230:Limit of Detection; D008297:Male; D010076:Oxazepam / Q000302:isolation & purification* / Q000652:urine*; D013050:Spectrometry, Fluorescence / Q000379:methods; D013053:Spectrophotometry / Q000379:methods
chemical_list: D014151:Anti-Anxiety Agents; D004396:Coloring Agents; D010076:Oxazepam